Category: Weather disasters

One more example of how countries in the poor part of the world will be hit by extreme weather and natural disasters as the globe heats up.

This study shows that there is a great likelihood that the weather in countries around the Indian Ocean is becoming more extreme due to cyclical changes in the ocean temperatures and the impact these have:

What do the torrential rains that swept across a swathe of East Africa in 1997 have in common with the record-breaking drought that Australia has just emerged from? Both can be blamed on El Niño’s Indian Ocean sibling.

A study looking at how climate change will affect this ocean oscillation pattern has predicted that if the world is allowed to warm uncontrollably, these kinds of extreme events will become the norm by 2050.

The Indian Ocean Dipole (IOD) is an oscillation of warm water across the equator. In the oscillation\’s positive phase, sea surface temperatures in the Arabian Sea rise whereas temperatures around Sumatra, Indonesia, fall. In the negative phase, it’s the other way around.

As well as being blamed for Australia’s recent dry spell and the 1997 East African storms, the IOD\’s positive phase has been linked to droughts in Australia and dry weather in Indonesia over the last 6500 years, according to a 2007 study of fossilised coral. The study also concluded that positive events are becoming more frequent, with an unprecedented 11 occurrences over the past 30 years.

You might have seen the pictures of floods in Colorado, USA. Here is a piece explaining how the once-in-a-1000-year rainfall was made even worse by the huge wildfires, the area has experienced the last years. Again, an example of how things on our Planet are interconnected, and that we need to take care of all sides of it.

18 September 2013 by Alyssa Botelho

A TRULY ferocious and exceptional event. That’s how Kevin Trenberth of the National Center for Atmospheric Research in Boulder, Colorado, describes the storm that pummelled his state last week. “This was a once-in-1000-year rainfall.”

The torrential rains and subsequent floods have so far killed eight people, displaced 11,750 and destroyed close to 18,000 homes. The city of Boulder received a year’s rainfall in less than a week, says Daniel Leszcynski at the National Oceanic and Atmospheric Administration. That huge volume was due in part to a lingering heatwave that for months blocked tropical moisture from the Gulf of Mexico from reaching the Rockies, he says. When that heatwave began to move east last week, weak winds allowed the growing storm system to sit above the Colorado peaks for days.

Once that deluge hit the ground, more trouble awaited. Recurring wildfires near Boulder and Fort Collins in recent years had cleared the land of vegetation that would normally absorb rainwater in these areas.

Though natural disasters are difficult to attribute to climate change, Trenberth says that the 1 °C rise in ocean temperature since the 1970s accounts for 5 per cent more moisture in today’s atmosphere. That’s enough to invigorate already powerful storms such as last week’s, he says.

Here you can read about how huge devastating fires are becoming more common and how Global Warming will lead to more of this kind.

28 August 2013

SAN FRANCISCO is in a state of emergency, its power and water supplies threatened by one of the largest Californian wildfires on record – just 250 kilometres to the east of the city, on the fringes of Yosemite National Park. It is a grim warning of profound changes that may lie ahead. Wildfires have always been a part of life in the US west, but activity is on the rise as climate change takes hold. In Californias Sierra Nevada mountains, the main problem is the earlier onset of spring. “The snow melts earlier, especially at lower elevations,” says Michael Wehner of the Lawrence Berkeley National Laboratory. That gives forests longer to dry out, producing tinderbox conditions by late August. As New Scientist went to press, the Rim Fire had torched over 700 square kilometres and was approaching the Hetch Hetchy reservoir, which provides San Francisco with most of its water and generates hydroelectric power for the citys General Hospital, transit system and airport. It serves as a warning that wildfires can have effects far beyond the area they burn.